386 MINOR PRODUCTS OF PHILIPPINE FORESTS 



importations into the United States in 1907 was 26,252 dollars. 

 The greater part came from Burma. 



In the Philippines the rhizome is used for dyeing mats and 

 also as a condiment and coloring in food preparations. 



Krauch * states that the Curcuma rhizomes contain two yellow 

 dyes ; one of these is soluble in w^ater, the other in alcohol. The 

 water-soluble dye is not sensitive to alkalies, but the alcohol- 

 soluble dye (turmeric) is sensitive to both acids and alkalies 

 and is therefore used as an indicator in analytical chemistry. 

 The sensitiveness of the turmeric as an indicator is increased 

 considerably if the water-soluble dye is first extracted from the 

 Curcuma rhizomes with a large quantity of water and the rhi- 

 zomes then treated with alcohol for the preparation of the al- 

 cohol-soluble dye. Turmeric is insoluble in water. It dissolves 

 readily in ether, alcohol, acetic acid, alkalies, fats, and oils. 

 Solutions of turmeric are bleached when exposed to sunlight. 

 They show a green fluorescence and yield brown, insoluble lakes 

 with lead, lime, and barium hydroxides. Turmeric has a yellow 

 color in acid solutions and in alkalies gives intensely reddish- 

 brown solutions. The sensitiveness of turmeric indicator papers 

 is increased by the presence of salts. The indicator is therefore 

 useful in many different kinds of volumetric analyses. It can 

 be used in the presence of ammonia, but not in the presence of 

 carbonic acid. 



Turmeric is one of the best known of the natural dyes, that 

 is, those obtained from vegetable sources and not prepared syn- 

 thetically. It dyes silk, wool, and cotton bright shades of yellow. 



Concerning the dyeing properties of turmeric, Perkin and Eve- 

 rest t say : 



The tinctorial properties of curcumin are of special interest, for not 

 only is it a strong colouring matter towards mordants, but with cotton, 

 wool, and silk it behaves also as a substantive dyestuff. In the latter 

 case it is only necessary to add the material to a boiling decoction of the 

 colouring matter. Though considerably employed up to within recent 

 years by the wool and silk dyer in the formation of olives, browns, and 

 other compound colours, turmeric is now but rarely used for dyeing pur- 

 poses in England. In India, however, it appears to be still in vogue. 



Cotton is usually dyed in a decoction of turmeric rendered slightly 

 acid bv the addition of a little acetic acid, or alum may be employed. 

 The colour does not resist either the action of light or of alkalis, and readily 

 acquires a brov^nish-red tint. Wool may be dyed without any addition, 

 keeping the temperature about 60°. By previously mordanting with alum 



* Krauch, C, Testing of chemical reagents for purity. 

 t Perkin, A. G., and Everest, A. E., The natural organic colouring 

 matters (1918), page 395. 



